Air circuit breakers, as described within U.S. Pat. No. 3,095,489 entitled xe2x80x9cManual Charging Means for Stored Energy Closing Mechanisms of Electric Circuit Breakersxe2x80x9d and U.S. Pat. No. 3,084,238 entitled xe2x80x9cRatchet Mechanism for Charging a Closing Spring in an Electric Circuit Breakerxe2x80x9d, include operating mechanisms that are mainly exposed to the environment. Since the air circuit breakers are rated to carry up to several thousand amperes of current continuously, the exposure to convection cooling air assists in keeping the operating components within reasonable temperature limits.
Various accessory devices are used with such air circuit breakers to provide auxiliary function along with overcurrent protection. One such accessory is the bell alarm accessory that provides local and remote indication as to the occurrence of circuit interruption. U.S. Pat. No. 5,502,286 entitled xe2x80x9cBell Alarm and Lock-Out for High Ampere-Rated Circuit Breakersxe2x80x9d describes a bell alarm accessory used with so-called xe2x80x9cinsulated casexe2x80x9d circuit breakers wherein the circuit breaker interrupting components are completely enclosed within an insulating plastic enclosure.
U.S. Pat. No. 5,986,225 filed on Jun. 19, 1997 entitled xe2x80x9cCircuit Breaker Bell Alarm Accessory with Lockoutxe2x80x9d describes a bell alarm accessory for use with a high ampere-rated air circuit breaker that provides local as well as remote indication of such circuit interruption as well as preventing circuit breaker contact closure until and unless the bell alarm accessory has been manually reset.
High ampere-rated air type circuit breakers operate in the range of 2500 to 5000 amperes such that the large circuit breaker operating components are arranged air type circuit breakers, that operate in the range of 150 to 1500 amperes, require bell alarms with lockout function to prevent contact closure until the bell alarm unit is reset, the arrangement of the circuit breaker smaller operating components do not allow the use of the high ampere-rated bell alarm reset accessory.
U.S. Pat. No. 6,054,661 entitled xe2x80x9cCircuit Breaker Bell Alarm Accessory with Lockout Functionxe2x80x9d filed concurrently with this application describes a low ampere-rated air circuit breaker that includes an arrangement for preventing the circuit breaker contacts from becoming closed until the bell alarm module has become manually reset. U.S. Pat. No. 6,242,703, dated Jun. 5, 2001 B1, entitled xe2x80x9cCircuit Breaker Bell Alarm Accessory with Automatic Reset for Small Frame Air Circuit Breakerxe2x80x9d filed concurrently with this application further describes an arrangement for automatically resetting the bell alarm accessory within a low ampere-rated air circuit breaker during the early stage of the circuit breaker closing spring charge cycle.
One approach to an arrangement that allows alternative bell alarm automatic reset function reset or bell alarm lock-out function within one accessory apparatus within high ampere-rated air circuit breakers is found in U.S. Pat. No. 5,960,941 filed Aug. 8, 1997 entitled xe2x80x9cCircuit Breaker Bell Alarm Accessory with Both Automatic Reset and Lock-out Functionxe2x80x9d.
In view of the size and component design differences between the high ampere-rated and low ampere-rated air circuit breakers described earlier, the high ampere-rated combined bell alarm accessory would not function within low ampere-rated air circuit breaker enclosures. The purpose of the instant invention is to describe an arrangement for allowing selection between bell alarm automatic reset and automatic lock-out function in low ampere-rated air circuit breakers.
A combination bell alarm lock-out and bell alarm automatic reset accessory unit alternatively interacts with the circuit breaker closing system to prevent charging of the circuit breaker closing spring until and unless the bell alarm module has been manually reset in one option and interacts with the circuit breaker closing system to automatically reset the bell alarm accessory during charging of the circuit breaker closing spring in another option. The combination accessory support plate includes a first aperture to allow the bell alarm lockout plunger to interact with a first part of the closing system for automatic reset and includes a second aperture to allow the bell alarm lockout plunger to interact with a second part of the closing system to prevent closure of the circuit breaker closing spring until the bell alarm accessory is reset. The position of the bell alarm accessory on the accessory support plate determines which of the two apertures within which the lockout plunger becomes inserted.